prior to the Introduction of the Potentials. 41 



dtfiucnt stream of the same fluid entering the body from outside. 

 Light bodies in the vicinity, being caught in one or other of 

 these streams, are attracted or repelled from the excited electric. 



Nollet's theory was in great vogue for some time ; but six or 

 seven years after its first publication, its author came across a 

 work purporting to be a French translation of a book printed 

 originally in England, describing experiments said to have been 

 made at Philadelphia, in America, by one Benjamin Franklin. 

 "He could not at first believe," as Franklin tells us in his 

 AutobiograpJvy, " that such a work came from America, and said 

 it must have been fabricated by his enemies at Paris to decry 

 his system. Afterwards, having been assured that there really 

 existed such a person as Franklin at Philadelphia, which he had 

 doubted, he wrote and published a volume of letters, chiefly 

 addressed to me, defending his theory, and denying the verity 

 of my experiments, and of the positions deduced from them." 



We must now trace the events which led up to the discovery 

 which so perturbed Nollet. 



In 1745 Pieter van Musschenbroek (6. 1692, d. 1761), 

 Professor at Leyden, attempted to find a method of preserving 

 electric charges from the decay which was observed when the 

 charged bodies were surrounded by air. With this purpose he 

 tried the effect of surrounding a charged mass of water by an 

 envelope of some non-conductor, e.g., glass. In one of his 

 experiments, a phial of water was suspended from a gun- 

 barrel by a wire let down a few inches into the water through 

 the cork; and the gun-barrel, suspended on silk lines, was 

 applied so near an excited glass globe that some metallic fringes 

 inserted into the gun-barrel touched the globe in motion. 

 Under these circumstances a friend named Cimaeus, who 

 happened to grasp the phial with one hand, and touch the gun- 

 barrel with the other, received a violent shock ; and it became 

 evident that a method of accumulating or intensifying the 

 electric power had been discovered.* 



* The discovery was made independently in the same year by Ewald Georg 

 von Kleist, Dean of Kumrain. 



